Electrically-operated-machine-tool.



N0. 660,80l, Pa zemed But. 3%, ENE-"3.

J RHJBELL.

ELEGTRIGALLY GPERATEE MACHWE TGHL.

(Application filed Aug. 30, 1900.)

(No Model.)

Hh iall llt'il Witnesses rs: NUIERIS PETERS cm, WASHINGTON, u. c.

adjusting the machine.

UNITED STATES PATENT OFFICE.

JOHN RIDDELL, OF SOHENEOTADY, NEW YORK, ASSIGNOR TO THE GENERAL ELECTRIC COMPANY, OF NEW'YORK.

ELECTRlCALLY-O PER/\TED -MAOl-ilNE-=TOO-L.

SPEGIF ICATION forming part of Letters Patent No. 660,801, dated October 30, 1900. Application filed August 30, 1900. Serial No. 28,572. (No model.)

This invention relates to electrically-d riven tools, the object being to permit the tool to be driven at a variable rate of speed without me cessity of changing the gearin In working large pieces in a lathe much time is lost in change of speed at the point.

on which the tool is working as it inoves inwardly toward or outwardly i'rom the center,

since if the toolcnts rapidly on outer parts of the work it must out very slowly when it gets near the center, as the circle over which it travels is of much less diameter, and ii changeable gearing is provided for efiecting a change of speed considerable time is lost in On the other hand, if a hand-rheostat is used constant attention of the operator is required. In large boring and turning mills this is particularly evident where the cutting-tool may have a range of motion of ten or fifteen feet. Obviously unless means are provided for changingthe relative rate of travel of the tool and the work a very slow rate of cutting will vbe effected on the central parts of the work.

It is the object of'my invention to automatically adjust the conditions so that the tool may be given a continuous and uniform rate of travel with relation to the work. 1 effect this result by driving the machine by an electric motor and automatically changing the motor connections the cutting-tool travels over the Work, so that a uniform rate of cutting will be maintained on all parts of the work.

My invention is applicable "to all types of tools in which a relative rotation of the tool and work is etfected-such as lathes, boring and turning1nills,&c.rneansbeingprovided for automatically increasing the speed of the motor as the cutting proceeds from the center outward, and vice versa.

The novel features of 'myinvention will be more fully hereinafter described and will be definitely indicated in the claims appended to this specification.

- In the accompanying drawingsmhich illustrate my invention as-applied to a boring and turning mill, Figure 1 is a plan view of an organization embodying my improvements. Fig. 2 is a side elevation. Fig. 3 is an enlarged detail of the cutter-head and guide or cross-slide, and Fig. 4 is a diagram showing one form of control-circuits and mechanirnn for effecting the necessary changes of motor speed.

1 represents a turn-table or revolving support for the work, which is geared to the shaft of an electric motor 2,as will be clearly evident from Figs. 1 and 2.

3 represents a cutter-head in which an ad justable cutter-bar 3 for the cuttingtool 3" is mounted. This tool is provided with gearing by which it may be hand-operated or driven by the same source of power which rotates the bed 1,1neaus being provided for moving the tool vertically or horizontally, ac cording to the character of the out desired. 7:

is tools of this character are of usual construction and are well known to those familiar with the construction of machine-tools, I deem it unnecessary to describe its parts in detail, the drawings representing the operative parts of the tools simply to exemplify the application of my speed-controlling apparaius.

I mount on the cutter-head a contact device which as it moves to and fro with relation to the work automatically changes the voltage on the field and armature of the driving electric motor, either or both, to maini a. uniform cutting rate. This contact ocvic. is illustrated at l (see Figs. 1 and e) and comprises two bridging contacts insulated from one another, one of which varies the electrolnotive force on the armature of the motor and the other on the field, bot-h. bearing in the travel of the cutter-head upon a slide 5, upon which are mounted rail conductors and contacts for effecting the neces sary changes of voltage This slide is mount-- ed on a fixed part of the machine, as the crossslide, but is adjustable with relation to the line of travel of the cutter-head, as indicated in Fig. 1, means being provided for shifting i. '116 Other terminal on a or" the system m 1 for n posmve mai m" (i. nnum voltage and the field-nmgn'ets the met-pr-arnmturi censor "-a'djusting the slide 0, upon which the contacts are carried, an outward shifting of the slide increasing the speed of cutting and an inward shitting decreasing the same, since it is evident that if the slide is pulled out a higher voltage imposed upon the armature and the speed of the motor accordingly increased.

What I claim as new, and desire to secure by Letters Patent of the United States, is-

1. The combination with amachine-tool, of a drivingelectric motor and means for automatically varying the speed of the motor to control the speed of the tool.

2. The combination with a machine-tool, of a driving electric motor, a speed-controller for the motor, and mechanical connections with the machine for operating the controller.

3. The combination with a machine-tool, of a driving electric motor, a speed-controller for the motor, and connections for operating the controller to vary the motor speed as the cutting shifts to or from the center of the Work.

i. The combination with a tnrningmill or similar machine-tool, of a driving electric motor, a speed-controller for the motor, mechanical connections for operating the controller as the cutter moves to from the center of the Work.

5. .The combination with a turning-mill or similar machine-tool, of a driving electric motor, a speed-controller, and connections for varying the voltage on the field-magnet and armature of the motor as the cuttingtocl shifts to and from the center of the Work.

6. The combination with a turning-mill or similar machine-tool, of a driving electric motor, a speed-controller for the motor, and connections for raising the voltage on the motor as the cutting-tool shifts toward the center of the work.

7. The combination with a turning-mill or similar machine-tool, of a driving electric motor, a resistance in the motor-circuit, and a contact device to automatically reduce the resistance as thecntting-tool moves toward the center of the Work.

8. The combination with a turning-mill or similar machine-tool, of a driving electric motor, a speed-controller therefor comprising a variable resistance and connections for cutting ont resistance to raise the motor speed and maintain a uniform rate of cutting its the tool shifts toward the center of the work, and vice versa.

9. The combination with a turning-mill or similar machinetool, of a'driving electric motor, speed-controlling resistance in the field-magnet and armature-circuit of the motor, and contacts governed by the mill for varying said resistance to maintain a uniform cutting rate the cutting-tool shifts to dilferent parts of the work:

10. The combination of a turning-mill or similar machine-tool, of an electric motor, a supply-circuit delivering different voltages, and connections for automatically charging the leads connecting the motor and mainsas the cutting-tool shifts to or from the center ofthe Work.

11. The combination of a turning-mill or similar machine-tool, of a driving electric motor, fixed speed-controlling contacts mounted on a stationary part of the mill, and a movable contact device operated bythe mill to vary the speed of the motor.

12.- The combination of a tnrningmill or similar machine-tool, of a driving electric motor, a range of speed-controlling contacts, a relatively-movab1e contact device operated by the mill to vary the speed of the motor, and means for adjusting the startingpoint of the contact device relatively to the range of contacts.

13. The combination of n turning-mill or similar machinetool, of a driving electric motor, a. range of speed-controlling contacts for the motor, connections with the field-ma net and armature-circuits of the motor, a

supply-circuit for delivering a plurality of voltages, and a contact device operated by the mill for gradually varying the voltages on the armature and field to accelerate the motor speed as the cutting-tool moves tcwardthe center of the Work.

is. The combination of a turning-mill or other machine-tool, of a driving electric motor, rheostatic contacts mounted on the crossslid'e connecting respectively with the fieldmagnet and armature-circuits of the motor, and insulated contacts carried by thecntterhead for engaging the rheostatic contacts consecutively and varying the motor speed-as the cutting-tool shifts over the work to maintain uniform the rate of cutting.

In witness whereof I have hereunto set my hand this 29th day or August, 1900,

JOHN RKDDELL. Witnesses:

BENJAMIN HULL, EDWARD WiLLIAMs, J r. 

